Blackened, denuded tree trunks stand grimly on these hills in southeastern Borneo, nature's memorial cemetery for what conservationists call the ecological disaster of this century and the most destructive forest fire in recorded history.

Underneath these huge sticks that were a tropical forest, the ground is lush with rattan plants, banana trees, jungle shrubs -- a landscape like many another in the Indonesian archipelago, but it will be thousands of years, if ever, before this becomes primary rain forest again, biologists say.

From the fall of 1982 to the summer of 1983, fire consumed more than 8.6 million acres of tropical rain forest on Borneo island in the province of East Kalimantan. It is a swath of destruction about the size of Delaware and Maryland combined.

The fire enshrouded almost all of Borneo in a pall of smoke, turning day to dusk for weeks at a time, and disrupting air traffic. The smoke cloud moved across the Java Sea at one point, causing the airport to close in the east Java capital of Surabaya. The slow-moving fire did not cause any human casualities but took an unknown toll on wildlife and their habitats, including orangutans and gibbons, boars and bears, deer and leopords, hornbills and other exotic birds.

Environmentalists and government officials are still not certain how the fire started and what impact it is having on the climate and ecology of the island. Minister of Environment and Population Emil Salim told parliament recently that a full report of the disaster probably will not be ready until the year 2000.

But the Paris-based International Union for the Conservation of Nature and other environmental organizations described the great fire of Borneo as the biggest ecological disaster of the 20th century and the worst forest fire in recorded history.

That judgment is based not only on the massive destruction of increasingly scarce primary rain forest, including the loss of about $6 billion in timber, but on the untold destruction of potentially valuable plant species.

"It's reckoned that 10 percent of the flowers and plants in the rain forest have potential use, either as new crop plants or medicinal drug plants," said Dr. John Feltwell, a British botanist doing research in Indonesia. "About 96 acres of tropical forest are disappearing every minute. That's an area the size of Wales every day. Maybe in 170 years it will all be gone, so it's vital that we find these species before they become extinct."

Indonesia has more than 271 million acres of tropical forest -- second largest after Brazil. More than 20 percent of the destruction of rain forests occurs in Indonesia, mostly due to illegal tree felling and slash-and-burn agriculture, according to government figures.

Indonesian officials and environmental organizations believe that the forest fire on Borneo probably was started by nomadic tribesmen practicing slash-and-burn cultivation. Old logging roads slice through much of the forest, providing easy access to the nomads.

The fire was preceded by the worst drought in Indonesia in a century, reportedly a result of the shifting El Nino Pacific current. The drought had turned the normally moist forest floor into crackling tinder, so the fire traveled along the ground, burning peat and coal deposits in the forest floor as deep as six feet.

The fire was followed by floods, which still plague east Kalimantan.

"The forests can no longer absorb the rainwater,"said Emma Darsono, director of the private Indonesian environmental organization, Wahli. "The rainwater and mud from the forests are flooding the rivers. Most of the tribes there live along the river banks, and now they've had to migrate. The people there say it's hotter now than it used to be."

Here in Bukit Suharto (Suharto's hill), about 500 persons, who were shifted from Java to cultivate plantation crops, moved again when the fire swept through. Now the area is eerily quiet, with only the chirping of insects to break the deathly stillness.

The government is planning to turn vast areas of the burned forest into plantations and again bring families from Java to do the work. About 3.3 million acres have been set aside for this purpose. About 4 million acres are supposed to be reforested, and 500,000 acres will be left to nature's designs, according to the Ministry of Forestry.

The forest fire had the effect of stirring the Indonesian government from its complacency about its forest wealth. "We are learning from our experiences in the East Kalimantan fire," Forestry Minister Sudjarwo said.

The ministry has launched a crash program of forest firefighting and prevention, he said. Cargo planes will be used to airlift firefighting equipment. Laws forbidding slash-and-burn agriculture will be enforced more vigorously, he said. Indonesian scouts are being mobilized to set up firefighting brigades in villages around the forests.

"We can't afford sophisticated equipment. We don't have the money," said a senior East Kalimantan forestry official, "but what we do have is manpower, so that at the first sign of fire we can send them in.

"When the fire started, everybody was confused," he said. "We didn't have the ability to fight a fire like that, and we still don't.

"It will take hundreds, maybe thousands, of years for the jungle to grow back the way it was," the forestry official said. "Now the government and the people have learned that it is not enough to just take the wood out of the forests. They need to be managed and protected, too."